How to get RGB values from UIColor?

Question

I\'m creating a color object using the following code.

curView.backgroundColor = [[UIColor alloc] initWithHue:229 saturation:40 brightness:75 alpha:1];
         


        

Answer 1

Since iOS 2.0 there is a private instance method on UIColor called styleString which returns an RGB or RGBA string representation of the color, even for colors like whiteColor outside the RGB space.

Objective-C:

@interface UIColor (Private)

- (NSString *)styleString;

@end

// ...

[[UIColor whiteColor] styleString]; // rgb(255,255,255)
[[UIColor redColor] styleString]; // rgb(255,0,0)
[[UIColor lightTextColor] styleString]; // rgba(255,255,255,0.600000)

In Swift you could use a bridging header to expose the interface. With pure Swift, you will need to create an @objc protocol with the private method, and unsafeBitCast UIColor with the protocol:

@objc protocol  UIColorPrivate {
    func styleString() -> String
}

let white = UIColor.whiteColor()
let red = UIColor.redColor()
let lightTextColor = UIColor.lightTextColor()

let whitePrivate = unsafeBitCast(white, UIColorPrivate.self)
let redPrivate = unsafeBitCast(red, UIColorPrivate.self)
let lightTextColorPrivate = unsafeBitCast(lightTextColor, UIColorPrivate.self)

whitePrivate.styleString() // rgb(255,255,255)
redPrivate.styleString() // rgb(255,0,0)
lightTextColorPrivate.styleString() // rgba(255,255,255,0.600000)